Shuttleless looms of the type to which the present invention is applicable have opposed carrier elements which are attached to the free ends of flexible tapes. The opposite ends of these tapes are fixed to a point on the outer peripheral surface of oscillating tape wheels disposed at the sides of a loom. The carrier elements are caused to enter a warp shed and to be withdrawn therefrom by the wrapping and unwrapping of the flexible tapes on and from their respective tape wheel.
As is well known to those familiar with the art, this type of loom utilizes an outside source of weft, that is, the supply is not carried to and fro through the warp shed by a shuttle or the weft inserting member itself. The weft yarn is measured and cut to the required length for extending across the width of the fabric being woven.
A first carrier inserts the weft into the warp shed to a point adjacent the center thereof where it is then transferred to a second carrier member which extends it through the remaining portion of said shed to complete the laying of a single pick.
The tape wheels are oscillated slightly less than a full revolution and as the tapes are being withdrawn from the shed they are wrapped tightly about the peripheral surface thereof. When the tapes are being unwrapped or extended from their respective wheel and inserted into the shed, guide elements are required to hold them radially inward and in close proximity with the rim of said wheels.
A number of U.S. Patents describe and clearly illustrate the looms and mechanism for actuating flexible tapes and carriers by means of oscillating tape wheels and it is considered unnecessary at this point to insert herein a detailed description of the mechanisms. Attention is hereby drawn to U.S. Pat. Nos. 2,604,123 and 2.810,403.
A common form of guide element utilized for maintaining the flexible tapes in close proximity with the rims of tape wheels is that of a plurality of arcuate shoe members made of such materials as impregnated wood or plastic. Additionally, other forms of guide elements have included devices such as a plurality of roller members for restraining the flexible tapes.
The known forms of tape restraining devices have not proven to be entirely satisfactory for, in most cases, considerable wear is introduced, and friction and heat are generated through the pressure of the moving tapes against their restraining means. The heat generated by the frictional contact of the tapes with the known forms of restraining devices, and especially the more common arcuated shoe type, is considered a problem, for excessive heating of the tapes will distort them to the extent where control of the tape and carrier settings at the weft transfer point is lost. Loss of this control often results in failure to transfer the weft from one carrier to the other as well as a more serious condition of carrier collision. A collision of the carrier members is known to be responsible for breakage of many warp yarns as well as resulting in excessive down time to replace or make the necessary repairs to the damaged carriers.
The present invention provides a tape wheel having a tape restraining means forming a part thereof which oscillates with the wheel and in timed relation to the weaving cycle is displaced to release the tape for insertion into a shed and thence returned to tape retaining position during the withdrawal of the tape from said shed. By having the tape restraining means mounted for movement with their respective tape wheels the above problem of generating excessive heat has been corrected thereby, providing a more positive control of the tapes and their carriers at the weft transfer point. Additionally, by eliminating the frictional contact between the tapes and the restraining means for holding them in close proximity with the rim of the wheel reduces substantially the power requirements for actuating the tape wheels.